Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Power-line communication (PLC) systems operate by adding a modulated carrier signal to an existing wiring system that is simultaneously used for electric power transmission or power distribution. By way of example, a PLC system may provide a means for networking electronic devices within a home or office together by communicating data over existing alternating current (AC) wiring between electrical outlets. As another example, a PLC system may provide a means for utility companies to communicate with customer utility meters over existing AC wiring between transformers and customer outlets.
Modern PLC technology can roughly be categorized into two categories: narrowband PLC and broadband PLC. Narrowband PLC is often used for low-bit rate communication (e.g., tens or hundreds of kilobits per second) over distances of several kilometers. Applications of narrowband PLC technology include automatic utility meter reading, and control of building or street lighting, for example. Narrowband PLC systems may occupy frequency bands below 500 kHz.
On the other hand, broadband PLC is often used for transmitting two-way data at higher bit-rates and over short ranges than narrowband PLC. For instance, broadband PLC is designed for communicating data over existing AC electrical distribution wiring (e.g., between transformers used for power distribution or between electrical outlets within a home). Broadband PLC systems may use modulation schemes such as orthogonal frequency division multiplexing (OFDM) or quadrature amplitude modulation (QAM). Broadband PLC systems may occupy frequencies that are part of the radio spectrum allocated to over-the-air communication services (e.g., 2 MHz to 80 MHz). Other types of PLC systems also exist.